ArrayList in Java | Collection Framework | Java Collections | Java Tutorial For Beginners

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ArrayList:

ArrayList is a class which implements List interface.
The underlying data structure for ArrayList is Resizable Array or Growable Array.
Duplicate elements are allowed
Insertion order is preserved.
Heterogeneous objects are allowed
null insertion is possible.

All the methods present in the ArrayList are Non-Synchronized.
So, multiple threads can allow to perform operations on ArrayList.
So, relatively performance is high because Threads are not required to wait.
ArrayList is best suitable for Retrieval operation.
But it is NOT best suite for frequent insertion or deletion operation in the middle of the Array as it requires multiple shift operations internally.